RCE in Craftcms Cms
CVE-2026-115935
The app/process-api-response-headers action accepts fake Craft API response headers from any authenticated control panel user. A non-admin user with only accessCp can place newline characters in X-Craft-Plugin-Licenses. Craft passes this value to its .env writer without removing the newlines. This lets the user insert a new attacker-known CRAFT_SECURITY_KEY into .env. After Craft loads that key, the user can forge a signed login redirect containing a Twig system() callback. This is different from the previous report. That report reads the existing key through a Twig sandbox bypass. This report replaces the key through fake API headers and CRLF injection. Fixing either source does not fix the other.
Vulnerability class: RCE (Remote Code Execution)
Published .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- 7004884b-51e2-48e8-b4a2-5ca29e80453e (technical-description, mitigation, third-party-advisory)
- 7004884b-51e2-48e8-b4a2-5ca29e80453e (release-notes)
- 7004884b-51e2-48e8-b4a2-5ca29e80453e (product)
- 7004884b-51e2-48e8-b4a2-5ca29e80453e (third-party-advisory)
Frequently asked questions
- What is CVE-2026-115935?
- CVE-2026-115935 is a high-severity vulnerability in Craftcms Cms, classified under Code Injection. CVSS score: 8.8/10. Published 2026-10-23.
- How severe is CVE-2026-115935?
- High severity. CVSS v3 base score is 8.8 out of 10.